Fixes commit id 648a60baf6. When
allow_use_first_unread_when_narrowing() is false last message of
narrow is shown in view.
Comments rewritten by tabbott to explain in detail what's happening.
This seems like a small change (apart from all the
test changes), but it fundamentally changes how
the app finds "topic" on message objects. Now
all code that used to set "subject" now sets "topic"
on message-like objects. We convert incoming messages
to have topic, and we write to "topic" all the way up
to hitting the server (which now accepts "topic" on
incoming endpoints).
We fall back to subject as needed, but the code will
emit a warning that should be heeded--the "subject"
field is prone to becoming stale for things like
topic changes.
This continues the effort to isolate "subject" references
to util calls.
Also, we fix a comment.
Finally, we use canonicalized operators in a switch
statement.
We now use narrow_state.filter() everywhere. The
two functions did the same thing, and I slightly
prefer the concise name, which was already in use
in lots of places.
Mohit Gupta
Steve Howell